(1) Field of the Invention
The present invention relates to an air bag device which is mounted on a vehicle. More specifically, the invention relates to an improvement in a construction for holding a pad in a bag holder. The pad covers a folded air bag.
(2) Description of the Prior Art
In the air bag device of the prior art, the folded air bag is covered with the pad. This pad is made of a synthetic resin and constructed to include a ceiling wall portion and a mounting wall portion. The ceiling wall portion is provided with a door portion. This door portion is opened by breaking its surroundings when the air bag expands. The mounting wall portion extends downwards from the outer peripheral edge of the ceiling wall portion.
Moreover, the air bag device is equipped with a bag holder for holding the air bag and the pad. The bag holder is made of a sheet metal, and is constructed to include a bottom wall portion and a side wall portion. The bottom wall portion is arranged under the ceiling wall portion so as to confront the ceiling wall portion of the pad. The bottom wall portion is constructed to hold the air bag on its upper face side. The side wall portion is extended vertically from the outer peripheral edge of the bottom wall portion. On the other hand, the side wall portion is arranged with the inner side of the mounting wall portion of the pad. This side wall portion holds the pad.
Moreover, two model types are provided in the prior art for holding of the pad by the bag holder.
First, one type is called the "clamping type" (as disclosed in Unexamined Published Japanese Patent Application No. 5-139236). The pad is provided, in the inner side face of the mounting wall portion, with retaining grooves which are extended horizontally. The pad is further provided with inserting grooves in the lower end face of the mounting wall portion. The bag holder is provided with retaining pawls at the upper end of the side wall portion. Below the bag holder, there is arranged a back-up plate which is connected to the bag holder. The back-up plate is provided with a vertical wall extended upward. For holding the pad, moreover, the retaining pawls of the bag holder are retained at first in the retaining grooves of the pad. Next, the vertical wall of the back-up plate is inserted from below the holder into an insertion groove of the pad. As a result, the lower portion of the pad is clamped between the retaining pawls and the vertical wall of the back-up plate so that the pad is held by the bag holder.
The other type is called the "rivet type" (as disclosed in Unexamined Published Japanese Patent Application No. 7-125596). The mounting wall portion of the pad and the side wall portion of the bag holder are individually provided at their corresponding positions with mounting holes extended therethrough. Moreover, the pad is held by inserting fixing means such as rivets into these mounting holes.
However, the former clamping type requires the back-up plate. This back-up plate is made of a sheet metal. This increases the weight of the air bag device of the clamping type.
On the other hand, the latter rivet type employs a doubling plate made of a sheet metal. This doubling plate is arranged on the peripheral edge of the fixing means on the outer side face side of the pad mounting wall portion. This doubling plate also increases the weight of the air bag device of the rivet type.